Purpose: To compare the outcomes of manual top hat penetrating keratoplasty (PK) versus traditional PK.
Methods: We reviewed the charts of 71 consecutive patients who underwent manual top hat (n = 36) or traditional (n = 35) PK at our institute. Main outcome measures included best-corrected Snellen visual acuity (BCVA), topographic and refractive results, high-order ocular aberrations, endothelial cell counts, and complication rate.
Results: No difference in mean BCVA between the 2 groups was noted after 12 months of follow-up. The mean spherical equivalent power was mild myopia, and the mean astigmatism was <4.2 D cylinder in both groups. There was no difference in total high-order aberrations, except spherical aberrations: 0.88 ± 0.74 μm in the top hat versus 0.49 ± 0.41 μm in the traditional PK (P = 0.01). Endothelial cell count was significantly higher in top hat PK group (1978 ± 277 vs. 1449 ± 516/mm2 in traditional PK; P < 0.0001), and time to all suture removal was shorter (3.9 ± 1.5 vs. 9.7 ± 1.1 months in traditional PK; P < 0.0001).
Conclusions: BCVA and refractive results are similar after manual top hat and traditional PK. Top hat PK speeds up suture removal and contributes to higher endothelial cell counts in the grafts 1 year after surgery.